Heavy-duty gear pump



Dec. 6, 1966 o, ECKERLE TAL 3,289,599

HEAVY-DUTY GEAR PUMP Filed April 6' 1964 :5 Sheets-sheet 1 Dec. 6, 1966 o. EcKr-:RLE ET AL HEAVY-DUTY GEAR PUMP 5 Sheets-Sheet 2 Filed April 6, 1964 5 W @W ,7 fu Hbf. g Ow. no @om MJ w w f 0 m J// Dec. 6, 1966 0` ECKERLE ET AL 3,289,599

HEAVY-DUTY GEAR PUMP Filed April 6, 1964 :3 Sheets-Sheet .'5

/n vena/5 UnitedStates Patent O 1 Claim. (ci. 10s- 126) This invention relates to gear pumps in which the teeth of a pinion mesh with internal teeth of an annulus of greater pitch diameter, and particularly to automatic wear compensation in a gear pump of the type described.

The invention is more particularly concerned with an improvement in the pump disclosed in the co-pending application Serial No. 229,272, led October 4, 1962, now United States Paten-t No. 3,136,261, which is equipped with a control device which holds a iioatingly mounted annulus in proper engagement with the pinion and an interposed filler or sealing member even with the annulus, the pinion, and the filler member are worn.

Specifically, the instant invention aims at providing proper cooperation of the control device with the operating parts of the pump to achieve automatic adjustment of their positions, eliminating the need for precise machining of these parts except for the diameter of the annulus which is readily achieved by cylindrical grinding.

The exact nature of this invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawing in which:

FIG. 1 shows a pump of the invention in radial section on the line A-B in FIG. 2;

FIG. 2 shows the pump in section on the axis of its drive shaft and on line C-D` in FIG. 1;

FIG. 3 shows the same pump in section on the line E-F in FIG. 2;

FIG. 4 shows a modified detail of another pump taken in section on the` line J-K in FIG. 6;

FIG. 5 shows a modied detail of the pump of FIG. 1, in axial section;

FIG. 6 shows another pump of the invention in section on the line EF in FIG. 7;

FIG. 7 shows the pump of FIG. 6 in a view corresponding to that of FIG. 2; and

FIG. 8 shows the pump of FIG. 7 in section on the Vline E-F in that gure.

Referring to the drawing in detail, and initially to FIGS. l to 3, there is seen a gear pump Ihaving a casing 7 Whose cavity 14 is closed by a cover 8, and a drive shaft 1 journaled in the casing and cover and carrying a pinion 2. The annulus 3 of the pump, whose pitch diameter is greater than that of the pinion 2, floats freely in the casing 7 and meshes with the pinion 2. A filler member 4 is interposed in the sickle-shaped space between the portions of the pinion 2 and the annulus 3 which are not engaged. The filler member 4 is guided on a pin 6 which is mounted in the casing 7 and the cover 8, parallel to the axes of the pinion 2 and annulus 3, and engages a notch or slot 5 in the ller member 4.

The annulus 3 is axially confine-d between a pressure plate 9 and a `disc 9 which are interposed between the annulus and radial Walls of the casing 7 and cover 8 in the pump cavity 14. A recess 10 in the plate 9 is circumferentially elongated about the axis of the shaft 1, as best seen in FIG. 3, and its radial width decreases in the direction of rotation of the shaft 1 which is clockwise, as viewed in FIGS. l and 3. The recess 10 is sealed 3,289,599 Patented Dec. 6, 1966 by 4an O-ring 11 and communicates with the high-pressure outlet of the pump by a bore 12.

The pin 6 passes an axial bore 13 of the pressure plate 9 with ample clearance, and a corresponding bore in the disc 9". It is the primary function of the plate 9 to seal the pressure side of the pump, and it need not be radially coextensive with the cavity 14.

The position of the annulus 3 in a plane transverse of the afore-mentioned axes is determined by its meshing engagement with the pinion 3 and by engagement of its cylindrical outer face with a conforming concave surface of a control member 15 in the pump cavity 14. The control member is abuttingly engaged by a centrally apertured plunger 17 which is slidably received in an outlet connector 16 attached to the pump casing 7. A circumferential recess |18 in the concave face of the control member 15 communicates with .the pressure chamber 21.1y of the pump between the teeth of the pinion 2 and annulus 3 by ducts 19 in the annulus. The recess 18 communicates with the outlet connector 16 through a bore in .the control member l15, and is so dimensioned that the effective surface area of the plunger 17 is slightly greater than that of the recess 18, whereby the control member 15 is urged by the pumped fluid radially against the annulus 3 with slight pressure. A portion of this pressure is transmitted by the annulus 3 to the liller member 4, and urges the latter toward the pinion 2.

It is the primary function of the disc 9 to protect the casing 7, which is preferably made of light metal, against wear by the pinion 2 and annulus 3.

The control member 15 is mounted in the casing 7 by a pin 21 which passes loosely through an axial opening 22 in the member 15 `and is xedly fastened to the casing 7 so that the control Imember 15 may swing inward of the cavity 14 as the meshing parts of the pump are worn down during use.

The circumferential face 23 of the plunger 17 which ,guides the plunger in the connector 16 and is equipped with a sealing ring 24 is narrow in the Idirection of its axis and convex in an axial plane to facilitate angular movement of the control member 15 about the bolt 2|1. A compression spring 25 arranged between the plunger 17 and the connector 16 holds the control member 15 in its operative position prior to starting of the pump while Huid pressure is not available for this purpose.

In the modied pump partly shown in FIG. 4, the pin 6 is mounted in the casing 7 and `the cover 8 by means of eccentrically bored discs 26, 27. The control member 15 shown in FIG. 5 is provided with a bore having enlarged orifices 2S, 29 to permit Wide tilting movement of the control member on the pin 221.

The pump shown in FIGS. 6 to 8 includ-es the modied detail seen in FIG. 4, and additionally differs from the embodiment of the invention described with reference to FIGS. =1 to 3 by Ithe provision of a second pressure plate 9 instead of the aforementioned disc 10.

The pin `6 loosely passes through the pressure plates 9, 9 which mainly serve as sealing members, and therefore need not be radially coextensive with the pump cavity 30.

The arcuate wall of the pump cavity 30 is cylindrical and coaxial with the shaft. This permits liquid to enter the gaps between the teeth of the pinion 2 and the annulus 3 on the intake side of the pump in an axial as well as a radial direction through the ducts 19* in the annulus 3.

As is best seen in FIG. 6, the contact faces 31, 32 of the cas-e 7 and of the cover 8, and the corresponding contact faces 33, 34 of the intake or suction connector 35 and of the output or pressure lconnector 36 are iden- J tical in shape, and the connectors are formed with conduits that make an angle of 45. The connectors may therefore be turned for attachment of downwardly directed pipes.

If the direction of rotation of the pump is to be changed, the connectors 35, 36 are interchanged, and the control member is `shifted from the recess 37 of the casing 7 to the recess 37.

The filler member 4 is turned and shifted from the pin 6 to another pin 6.

The shaft 1 is mounted in the modified gear pump in roller bearings 38 of which one is received in a bearing plate 39 equipped in one radial face with a recess 40 which communicates with the high-pressure side of the pump as described above with reference to the recess 10. The center of gravity of a similar recess 43 in the other face of the plate 39 is axially aligned with the center of gravity of the recess 40, and simil-ar, but smaller recesses 41, 42 are provided in the casing 7 and cover 8 adjacent the pressure plates 9, 9.

In order to achieve the transmission of power acting only on the point of the strongest effect of hydraulical pressure the pressure discs 9 and 9 of the bearing plate 39 respectively the case 7 and the cover 8 can be provided with a recess 41 and 42 each, so that the sealing planes are equally or smaller formed than the internal pressure recess.

What is claimed is:

A gear pump comprising, in combination:

(a) casing means defining a cavity therein;

(b) a drive shaft journaled in said casing means for rotation about a fixed axis;

(c) a pinion member mounted on said shaft in said cavity;

(d) an internally toothed annulus having a pitch diameter greater than the pitch diameter of said pinion member, said annulus being movably received in said cavity;

(e) control means engaging a circumferential portion of said annulus for urging the same in a direction toward said pinion member for meshing engagement with the same, whereby the engaged annulus and pinion member define therebetween a sickle-shaped space;

(f) an elongated filler member movably received in said space, said `filler member tapering from one toward the other of the longitudinally terminal portions thereof;

(g) first pin means loosely securing said one terminal portion to said casing means for pivotal movement of the filler member about a first pivot axis parallel to said fixed axis, and for limited movement of the filler member relative to said -pivot axis, said other terminal portion being received between said annulus and said pinion member and held in sealing engagement therewith by the engagement of said control means with said annulus, said control means including (l) a plunger member,

(2) means mounting said plunger member on said casing means for movement in said direction and for angular movement in -a plane parallel to said direction,

(3) a control member interposed between said plunger member and said annulus in said direction,

(4) second pin means securing said control member to said casing means for pivoting movement about a second pivot axis parallel to said fixed axis and for limited movement of the control member relative to said second pivot axis, and

(5) means for urging said plunger member in said direction for abutting engagement with said control member.

References Cited by the Examiner UNITED STATES PATENTS 1,604,802 10/ 1926 Brenzinger 103-120 1,646,615 10/1927 Furness 103-126 1,816,508 8/1931 Wilsey 103-126 2,124,140 8/1938 Foster et al. 103-126 2,996,999 8/ 1961 Trautman 103--126 FOREIGN PATENTS 1,335,455 8/1963 France.

325,849 3/ 1917 Germany.

References Cited by the Applicant German application E 18,095, Apr. 11, 1963. German application E 24,667, Apr. 11, 1963.

D MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

W L- FREEH? Assistant Examineff 

